Detecting objects in images has been used in many applications: auto tagging pictures (e.g. Facebook, Phototime), counting the number of people in a street(e.g. Placemeter), classifying pictures, … And even in Bistro, a device to feed cats.

This post is a small introduction to OpenCV an open source computer vision library using scala.
The OpenCV library provides several features to manipulate images(apply filters, transformation), detect faces and recognize faces in images.
In this post, we are going to implement two small scala programs:

read an image and run the Haar cascade classifier to detect the faces in the image